Xantia HDi engine died with a bang.

Tony589 · Post by **Tony589** » 21 Oct 2005, 19:33

Hi,
My Dad's Xantia HDi '01 reg has just died on him.
He described hearing a bang, then the dash lights came on as the engine had stopped.
I towed him home, suspecting the cambelt, but looking into the rocker cover I'm pretty sure I could see movement as he cranked the engine, although it was getting dark and visibility was poor.

The engine sounds to be turning over faster than I would expect, about the same speed as when I pull the plugs on my petrol engine to test compression.

The car has done about 106k miles and someone has written next to the cambelt cover "Changed at (smudged number) miles"

I will have another look tomorrow, but wondered if anyone has any ideas?

Cheers,

Tony.

fastandfurryous · Post by **fastandfurryous** » 21 Oct 2005, 20:12

If the cam belt had failed, I doubt the engine would crank over, as there would still be being piston/valve collisions.

That said, the HDi engine has rocker followers rather than direct acting bucket tappets, so you never know.

Someone (I can't remember who) on here has had an HDi engine with broken followers before, although his engine would run, but very roughly.

If the engine is spinning over, aprently without compression on any cylinders at all, there must be something fairly major broken!

Post by **Peter.N.** » 21 Oct 2005, 23:16

If its turning over as though it doesnt have any compression it probably hasn't, it could be if the camshaft is still turning that the belt has jumped a few teeth, but it would seem that all the valves are open,and as fastandfuryous says, it sounds expensive.

Tony589 · Post by **Tony589** » 25 Oct 2005, 12:40

Camshaft definately turning, Had a local mechanic come out, he says engine/compression is OK, Suggests having a diagnostic check done, thinking perhaps immobiliser or electrical fault.
Any reccomendations for a good diesel diagnostics place around bradford, preferably mobile? We rang one place but they only do petrol.

Does the HDi engine crank noticably faster than the Xantia TD?

Cheers,

Tony.

fastandfurryous · Post by **fastandfurryous** » 25 Oct 2005, 14:28

The question is not how fast it turns over, but more the sound it makes while it's doing it.

If it's a regular ruh-ruh-ruh-ruh-ruh-ruh, then you have compression.

if it's going ruh-ruh-whizz-ruh-ruh-ruh-whizz-ruh-ruh-ruh-whizz, then you've lost one cylinder's compression.

If it symply goes whizzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz, then you have naff all compression. This sound is very obvious indeed. Try removing all the glowplugs, and then spinning it over.... how different does it sound?

For an engine to stop with a "bang" suggests to me that it needs more than just diagnostics.

Is there any white smoke in the exhaust when you crank it? If so, this would suggest fuel being injected.

uhn113x · Post by **uhn113x** » 25 Oct 2005, 15:01

Tony589 wrote:Camshaft definately turning, Had a local mechanic come out, he says engine/compression is OK, Suggests having a diagnostic check done, thinking perhaps immobiliser or electrical fault.
Cheers,

Tony.

But, Tony, why the bang?

mbunting · Post by **mbunting** » 25 Oct 2005, 15:57

Sounds like a good one.

Could you describe where your father thinks the bang came from ( ie. front / back ) ?

Just thinking, could the turbo have broken up, sending bits down into the cat / silencer, and throwing the ECU out so much ( ie. multiple systems failure ) that it couldn't think of a limp home solution, so shut down ?

Tony589 · Post by **Tony589** » 26 Oct 2005, 15:53

Hi, Turns out the "bang" sounded something like the time his clutch cable clip broke on his Xantia TD, so probable not much of a BANG at all!
There is no smoke coming out of the exhaust. I found the fuel cut-off switch and pressed it, not sure if they are obvious when they have tripped? This one didnt seem to do much, i.e no click when pressed.
The engine turns with a "ruh-ruh-ruh-ruh-ruh-ruh", no whizzzzz.

We have called a diagnostics company from Halifax who are going to send a chap out. I'll let you know if he finds anything.

Cheers,

Tony.

Tony589 · Post by **Tony589** » 26 Oct 2005, 23:28

The diag man came with a box of tricks from Sun.

The tests showed a faulty "No1 cylinder reference sensor". Small grey sensor mounted through the rocker cover, above the No1 cylinder.

He is getting one for us. Hope thats all thats wrong.

I'll follow-up later.

Cheers,

Tony.

wheeler · Post by **wheeler** » 27 Oct 2005, 00:15

i think you will be wasting your money,the ECU only needs cylinder reference info from the cam sensor to start the engine,once it is running you can disconnect the sensor when the engine is running & it wont affect it,just wont start the next time.i'd guess that this fault has come up due to non syncronisation between the camshaft & crankshaft i.e. timing has jumped. the sensor is actually above cylinder no 4.

Tony589 · Post by **Tony589** » 27 Oct 2005, 00:21

Oh dear.

Which is the No4 cylinder? The sensor he removed was on the left hand side of the engine when viewed from the front.

Tony.

fastandfurryous · Post by **fastandfurryous** » 27 Oct 2005, 05:13

I think this was the No.4 cylinder as in general (and certainly XUD) engines are numbered from the flywheel end. Thus as you stand at the front of the car looking at the engine it is numbered 4-3-2-1

If the timing has indeed skipped a tooth, that would explain the bang (valve/piston colision possibly) and why it now won't start, but you do still have compression, and the camshaft is turning.

One wonders if the belt fitted at "smudge" miles was the correct belt, and was tensioned properly. HDI engines are not as easy as XUD ones to get the tension correct.

Tony589 · Post by **Tony589** » 27 Oct 2005, 19:02

Oh well, the Auto electrician has thrown in the towel.

The fuel pump is running up to pressure, the injectors are getting a pulse.

He had his scope on the crank sensor and the camshaft sensor simultaneously. The crank sensor was giving a string of pulses with a gap each revolution. The camshaft sensor showed a trace that IIRC switched Lo,Hi,Lo, then Hi for the rest of the cycle. The start of one of the short pulses coincided with the reference gap on the crank sensor trace, but he had no knowledge of whether this was the correct position.

He opened the top of the cambelt cover and reckons the belt is slack so it might have jumped a tooth, so we are going to have the timing checked.

Squinting at the smudged writing in daylight, it was changed at either 67,040 or 87,040 miles, but if were having the timing checked, we may as well have a new belt on too.

Thanks for all the ideas, I'll let you know how it goes.

Tony.

fastandfurryous · Post by **fastandfurryous** » 27 Oct 2005, 19:40

Be sure that whoever does the belt checks what the timing is before removing the belt, as if it is out, then you may also have to do some investigative work over the engine as the chances of the pistons and valves having gotten "up close and personal" is fairly high.

you may find that replacing the belt allows the engine to run, but with additional noise where either a valve has mushroomed, a rocker has bent, or a valve crown is twisted and no longer seals.

wheeler · Post by **wheeler** » 28 Oct 2005, 18:26

Tony589 wrote:The camshaft sensor showed a trace that IIRC switched Lo,Hi,Lo, then Hi for the rest of the cycle. The start of one of the short pulses coincided with the reference gap on the crank sensor trace, but he had no knowledge of whether this was the correct position.

that sounds about right for the sensors.the crank sensor is an inductive type & shoud give off an AC wave pattern,the cam sensor is hall effect & should give a Hi Lo square wave signal.